Thermal Bridging – Is your SAP assessor making your design look as good as it is?
Achieving required or desired energy performance arises from good design and construction in the following areas: U-values, air tightness and thermal bridging at junctions.
Thermal bridging is not a new issue or concept, but as the U-values of walls and floors has improved and airtightness has increased, the percentage of lost energy that passes through thermal bridges has increased. Therefore it has become increasingly important for to attend to thermal bridges. And for SAP assessors to sharpen their pencil and not use default values!
For masonry construction design help is available through a suite of details for which psi values have been calculated (a psi value is the measure of energy lost at a junction). Clients and architects should require SAP assessors to use these more accurate psi values associated with the actual details rather than default values in SAP.
Use of these details goes a long way to helping optimise fabric performance and is highly recommended. By having details with the associated psi values, compliance can be demonstrated without recourse to more expensive solutions. Their use can also help avoid the need for renewables.
For more information see http://www.modernmasonry.co.uk/